Removal of kathon by UV-C activated hydrogen peroxide:Kinetics,mechanisms,and enhanced biodegradability assessment

Kathon(CMI-MI),a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one(CMI)and 2-methyl-4-isothiazolin-3-one(MI),was extensively used in industry as a nonoxidizing biocide or disinfectant.However,it would show adverse effects on aquatic life when it is discharged into surface water.In this study,the removal performance,parameter influence,degradation products and enhancement of subsequent biodegradation of CMI-MI in UV/H_(2)O_(2)system were systematically investigated.The degradation rate of CMI-MI could reach 90%under UV irradiation for 20 min when the dosage of H_(2)O_(2)was 0.3 mmol·L^(–1).The DOC(dissolved organic carbon)mineralization rate of CMI-MI could reach 35%under certain conditions([H_(2)O_(2)]=0.3 mmol·L^(–1),UV irradiation for 40 min).kobs was inversely proportional to the concentration of CMI-MI and proportional to the concentration of H_(2)O_(2).The degradation rate of CMIMI was almost unchanged in the pH range from 4 to 10.Except the presence of CO_(3)^(2-)inhibited the removal rate of CMI-MI,SO_(4)^(2-),Cl^(-),NO_(3)^(-),and NH_(4)^(+) did not interfere with the degradation of CMI-MI in the system.It was found that UV/H_(2)O_(2)system had lower energy consumption and more economic advantage compared with UV/PS system by comparing the EEO(electric energy per order)values under the same conditions.Two main organic products were identified,namely HCOOH and CH_(3)NH_(2).There’s also the formation of Cl^(-)and SO_(4)^(2-).After UV and UV/H_(2)O_(2)photolysis,the biochemical properties of CMI-MI solution were obviously improved,especially the UV/H_(2)O_(2)treatment effect was better,indicating that UV/H_(2)O_(2)technology is expected to combine with biotechnology to remove CMI-MI effectively and environmentally friendly from wastewater.

Influence of inorganic salt on aerobic biodegradability of dyestuffs

In this paper, the influence of inorganic salt on aerobic biodegradability of dyestuffs was studied by means of semi continuous activated sludge method. It was found that: biodegradability of dyestuffs would decrease with the increase of the concentration of NaCl; however, biodegradability in the condition of NaCl=30 g/L was better than that in the condition of NaCl=15 g/L; in the three NaCl conditions, biodegradability of tested dyestuffs followed the following order: NaCl=0 g/L > NaCl=30 g/L>NaCl=15 g/L.

The Green Composites: Millet Husk Fiber (MHF) Filled Poly Lactic Acid (PLA) and Degradability Effects on Environment

This study provides an overview on green composites degradability. Practically, the main drawbacks of using natural fibers are their poor dimensional stability, degradability and high degree of moisture absorption. While, end use of product from natural fiber filled or reinforced composites has become subject of concern to material engineers and scientist. The major properties of natural fiber reinforced polymer composites are greatly dependent on the hydrophilic tendency and dimensional stability of the fibers used, morphology aspect ratio for long fiber, while voids for powder fibers. The effects of chemical treatments on cellulosic fibers that are used as reinforcements for thermoplastics were studied. The chemical source for the treatments is alkalization. The significance of chemically-treated natural fibers is seen through the improvement of mechanical properties. The untreated fiber composites degrade faster in municipal soil compared to treated fiber composites.

THE DEGRADABILITY OF PARTICULATE ORGANIC MATTER IN THE GIRONDE ESTUARY, FRANCE

The degradability of particulate organic matter(POM)in the Gironde Estuary(France)was measuredusing the incubation technique.The influence of sample treatment and incubation conditions on the re-sults was evaluated.A mathematical model was successfully used to describe the various degradationcurves.Results showed that the upstream POM had very high degradability;the central estuaryPOM had low degradability;and that the mouth POM degradability was between that of central POM(low degradability)and marine POM(high degradability).

Napier Grass Rumen Degradability in Sacco in Goats (<i>Capra hircus aegagrus</i>) Supplemented with Different Sources and Amount of Dietary Fats

The study aimed to explore the potential of dietary fats supplementation on the overall goat performance. Three (3) mature rumen-cannulated goats weighting 27.33 ± 1.53 kg housed in individual elevated metabolism stalls with customized fecal and urine collection tools with treatments replicated three times over time following the Complete Randomized Design (CRD). Animals were randomly selected on different dietary treatment at different cycle. For each cycle, animals were provided with 30% concentrate on the morning based on feed requirements {3% of their body weight (BW) dry matter (DM) basis} of the animals. Ad libitum feeding of Napier grass will follow thereafter. Clean drinking water were made available all the times in the respective animal watering troughs. The rumen-cannulated goats were supplemented with different levels of two dietary fats (VCO and Lard) with dietary treatment combinations as follows, Control and VCO and Lard at 3% & 5%. Degradability of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were collected sequentially in every cycle of the study. There were seven (7) days lag period in every cycle for the animals to return to each natural state. On the 8th day of every cycle, animals were given different dietary treatment. Sequential insertion of nylon bag was done on the 15th to 16th day (7 days after treatment). The results showed that degradability of the dry matter (DM) was noticed degraded exponentially on the first twelve hours of incubation and slower down in the next few hours until 48 hours. Crude protein, acid and neutral detergent fiber showed breakdown of components was observed in the first 48 hours of incubation. No significant difference (P > 0.05) among treatment means was observed in all parameters gathered. This implies that mature female goat diet cannot be influenced by dietary fats from two different sources (VCO and Lard) at 3% to 5% supplementation. Based on the study conducted, dietary fats supplementation on goats such as VCO and lard given at the maximum level of 5% level did not influence the nutrient degradability of Napier grass in the rumen until it reaches at 48 hours of incubation. Supplementing ruminant diets with dietary fat in goats could increase the energy density of the animal’s diet without adverse effect on rumen degradability. This simple, easy, and basic technique could also be applied to other animal species in pursuit of finding ways to formulate indigenous feedstuff materials that have potential nutritive values. Given the limitations such as the climatic and environmental constraints, this particular study would somehow serve as benchmark in conducting related researches in optimizing the conditions with respect to animal nutrition and feedstuff utilization. Thus, this study was done to augment productivity and to provide new opportunities for achieving enhanced growth performance in a way that alleviates poverty, improves food security and nutrition and promotes sustainable use of natural resources.

Effects of Inclusion of Different Levels of Ethiopian Thyme (Thymus schimperi Ronniger) as Natural Additive on Chemical Composition and In Sacco Dry Matter Degradability of Total Mixed Ration and Feed Ingredients

This study evaluated the effects of the inclusion of Ethiopian thyme (Thymus schimperi Ronninger) to natural pasture hay (NPH), noug seed cake (NSC), wheat bran (WB) and total mixed ration (TMR) on the chemical composition and in Sacco dry matter (DM) degradability of the feeds. The Thyme plant used for the study was collected from Dinsho and Tarmaber districts in the highlands of Ethiopia. Samples of the TMR and NPH, WB and NSC with or without thyme were divided into two parts and ground to pass through 1 mm screen for chemical analysis and 2 mm screen for in sacco DM degradability. The TMR contained 50% NPH, 32.5% WB, 14% NSC, 3% molasses and 0.5% common salt. The feed ingredients (NPH, WB and NSC) and the TMR were incubated without thyme or with thyme substituting the diet at 8%, 16% and 24% levels of treatments. The chemical composition of all the feeds differed significantly (P In sacco rumen dry matter degradability of NPH, WB, NSC and TMR was increased (P in sacco DM degradability of NPH at all incubation hours was higher (P Thymus schimperi plant up to a level of 24% DM in feed can reasonably stimulate the growth and activity of the certain rumen microbes that promoted an improvement in ruminal DM degradability of the diet with the thyme inclusion.

Degradability of absorbable sutures in tendon grafts following anterior cruciate ligament reconstruction

Objective To observe the degradability of absorbable sutures in tendon grafts and the histology of tendon healing in a rabbit model.Methods Semitendinosus tendons were harvested from 15 healthy adult New Zealand rabbits in this study.

Chemically Modified Lignin:Correlation between Structure and Biodegradability

Lignin is the most abundant heteropolymer based on aromatic subunits in nature.Large quantities of lignin are annually produced from pulping processes and biorefinery industries.Its unclearly defined structure and difficult biodegradation mainly limit its utilization.This work focused on the effect of hydroxylation of lignin on its microbial degradation.Butyloxy carbonyl-modified lignin,and hydroxylated-lignin were synthesized with di-tert-butyl dicarbonate and hydrogen peroxide,respectively,using lignin as raw material.The degradation of the modifiedlignins both by P.chrysosporium and B.subtilis were analyzed using UV-vis spectroscopy.Results revealed that the lignin degradation velocity raises with the increase hydroxylation level of lignin.Moreover,FTIR and 1H NMR analysis of the biodegradation products of lignin further indicated that higher content of hydroxyl groups in lignin facilitated the demethylation combined with the aromatic ring cracking in the presence of fungus and bacteria.

Basic Physical Properties and Degradability of Tungsten Wire Fibers

In order to explore the feasibility of tungsten filament as biomedical metal material,this article conducted a series of performance tests on two different thicknesses of black tungsten filament and two different thicknesses of white tungsten filament.It mainly tested the basic physical properties of the tungsten filament including the longitudinal cross-section of the fiber,the fiber diameter,the mechanical properties of the fiber and the biodegradability,and analyzed the results.The results showed that the breaking force of tungsten filament was about 3000MPa.And whether it was black tungsten filament or white tungsten filament,the larger the diameter,the greater the breaking force,and the breaking strength of the tungsten filament was much larger than the breaking strength of the steel wire.The larger the diameter of the tungsten filament,the slower the degradation rate.During the two months,the mass loss rate of the thick black tungsten filament was 59.40%,thin black tungsten filament was 83.88%,thick white tungsten filament was 47.39%,thin white tungsten filament was 72.29%,the degradation rate of thick tungsten wire was nearly half of the thin,and degradation mainly occured in the first months.

Mineral Concentrations and Rumen Degradability of Biodegraded <i>Enterolobium cyclocarpum</i>(Jacq) and <i>Pterocarpus santalinoides</i>(L’Her) with <i>Aspergillus niger</i>

The effects of solid state fermentation on the mineral concentrations and in sacco degradation characteristics of dry matter in two multipurpose tree leaves was investigated. Biodegraded Enterolobium cyclocarpum (EC) and Pterocarpus santalinoides (PS) leaves were previously inoculated with Aspergillus niger and incubated at 30&degC for five incubation periods (0, 7, 14, 21 and 28 days). After each incubation period, samples were oven dried at 60&degC, allowed to cool and ground for mineral analysis and in sacco dry matter degradability. Three fistulated West African Dwarf (WAD) rams (Ovis aries) were then used for the dry matter degradability. Five grams of each sample was emptied into nylon bag (Polymon, Switzeland) with pore size of 4 μ and effective size of 5 cm × 18 cm and incubated in the rumen of the fistulated animals for 6, 12, 24, 48, 72, and 96 h. The results showed that the mineral contents of biodegraded EC samples were affected by incubation period. Mean values of Ca, Cu, K, Na, and Zn were significantly increased (0.05), while mean values of Fe, Mg, and Mn were first reduced before significantly increasing (0.05). However, the composition of P showed significant reduction (0.05) up to day 28 where no change was observed. Mineral concentrations in biodegraded PS were also affected by incubation periods. Values of Ca, Fe, K, Mg, Mn, Na, and Zn were significantly increased (0.05). However values of Cu, and Fe only increased after day 14, while the value of P was reduced significantly over the different incubation periods. Potential degradability (PD) for biodegraded EC was highest at day 0 (50.79%) but not significantly different from potential degradability of longer incubation periods to day 28 (48.68%). PS had higher PD than EC. In spite of high PD values, PS comparatively degraded faster than EC. Effective degradability (ED) for EC was highest for day28 (36.71%) and not significantly different from days 21 (34.83%) and 7 (35.29%) but significantly different from days 0 (31.32%) and 14 (31.75%) respectively. However, the ED for PS was highest for day 0 (31.39) samples and significantly differed from other incubation periods, further increase in period only showed lower but similar ED values for days 7 (27.52%), 14 (26.76%), 21 (27.42%) and 28 (26.86%) respectively. In this study, the continued reduction in P concentrations in both biodegraded EC and PS suggest that Aspergillus niger has preferential demand for P and in sacco degradation showed increase in PD and ED values for fungal biodegraded EC and reduction in PS, suggesting improved quality of EC.

Effects of moisture content or particle size on the in situ degradability of maize silage and alfalfa haylage in lactating dairy cows

A study using four Holstein cows with ruminal cannulas was conducted to evaluate the degradability of different moisture content or particle size of maize silage and alfalfa haylage. The maize silage(MS; 20-mm length) and alfalfa haylage(AH; 40-mm length) samples were wet(wet maize silage, MSW;wet alfalfa haylage, AHW), dried(dried maize silage, MSD; dried alfalfa haylage, AHD), or ground to pass through a 2.5-mm screen(dried ground maize silage, MSG; dried ground alfalfa haylage, AHG). Samples were incubated in the rumen for 2, 6.12, 24.36.48, and 72 h. Cows were fed ad libitum and allowed free access to water. High moisture content treatment of MSW expressed a lower rinsing NDF and ADF degradability at 2 h(P < 0.05) compared with dried samples(MSD and MSG). Different moisture content and particle size had a significant impact(P < 0.05) on the NDF degradability at 72 h, ADF degradability at36.48, and 72 h, and ruminally degradable ADF. All of the highest values were observed in small particle size and low moisture content AHG treatment. Based on this study, sample processing, such as drying and grinding, should be considered when evaluating nutritive values of forages.

Degradability evaluation for natural material fibre used on fish aggregation devices(FADs)in tuna purse seine fishery

Purse seiners deploy large amounts of drifting fish aggregation devices(FADs)in all tropical oceans to catch tunas.These FADs are constructed with porous synthetic fibre netting,which are responsible for incidental mortality of sea turtles and sharks through entanglement,and can engage in ghost fishing if they are lost and abandoned.The use of natural or biodegradable materials to build FADs can effectively mitigate marine pollution and bycatch issues,and as such they are currently promoted by fisheries management organizations.This study evaluated the degradability of ropes made of common natural fibres;cotton rope(3-strand,96-thread,twisted,S-lay),jute rope(3-strand,13-thread,twisted,Z-lay)and sisal rope(3-strand,8-thread,twisted,Z-lay).Degradability was evaluated by measuring the breaking strength(cN/dtex)and retention ratio of rupture elongation.Results showed that jute rope and sisal rope experienced rapid reduction of strength which over the first month soaking in the sea fell by 66.8%and 46.9%,respectively.Cotton rope exhibited the most inert degradation behavior,with breaking strength maintained at half of the initial value at 10 months.The retention ratio of rupture elongation for jute ropes and sisal ropes fluctuated considerably in the following months after deployment,compared to the relatively stable change for cotton rope.Results suggested that among these congeners,cotton rope would be most preferable component for Bio-FADs with a 10-month minimum durability that matches the required lifetime of FAD fishing strategies.

Amino acid and mineral digestibility,bone ash,and plasma inositol is increased by including microbial phytase in diets for growing pigs

Background The effect of microbial phytase on amino acid and energy digestibility is not consistent in pigs,which may be related to the phytase dosage or the adaptation length to the diet.Therefore,an experiment was conducted to test the hypotheses that increasing dietary phytase after an 18-day adaptation period:1)increases nutrient and energy digestibility;2)increases plasma P,plasma inositol,and bone ash of young pigs;and 3)demonstrates that maximum phytate degradation requires more phytase than maximum P digestibility.Results Data indicated that increasing inclusion of phytase[0,250,500,1,000,2,000,and 4,000 phytase units(FTU)/kg feed]in corn-soybean meal-based diets increased apparent ileal digestibility(AID)of Trp(quadratic;P<0.05),and of Lys and Thr(linear;P<0.05),and tended to increase AID of Met(linear;P<0.10).Increasing dietary phytase also increased AID and apparent total tract digestibility(ATTD)of Ca and P(quadratic;P<0.05)and increased ATTD of K and Na(linear;P<0.05),but phytase did not influence the ATTD of Mg or gross energy.Concentrations of plasma P and bone ash increased(quadratic;P<0.05),and plasma inositol also increased(linear;P<0.05)with increasing inclusion of phytase.Reduced concentrations of inositol phosphate(IP)6 and IP5(quadratic;P<0.05),reduced IP4 and IP3(linear;P<0.05),but increased inositol concentrations(linear;P<0.05)were observed in ileal digesta as dietary phytase increased.The ATTD of P was maximized if at least 1,200 FTU/kg were used,whereas more than 4,000 FTU/kg were needed to maximize inositol release.Conclusions Increasing dietary levels of phytase after an 18-day adaptation period increased phytate and IP ester degradation and inositol release in the small intestine.Consequently,increasing dietary phytase resulted in improved digestibility of Ca,P,K,Na,and the first 4 limiting amino acids,and in increased concentrations of bone ash and plasma P and inositol.In a corn-soybean meal diet,maximum inositol release requires approximately 3,200 FTU/kg more phytase than that required for maximum P digestibility.

Photocatalytic application of magnesium spinel ferrite in wastewater remediation:A review

This review paper explores the efficacy of magnesium ferrite-based catalysts in photocatalytic degradation of organic contaminates(antibiotic and dyes).We report the influence of different doping strategies,synthesis methods,and composite materials on the degradation efficiency of these pollutants.Our analysis reveals the versatile and promising nature of magnesium ferrite-based catalysts,offering the valuable insights into their practical application for restoring the environment.Due to the smaller band gap and magnetic nature of magnesium ferrite,it holds the benefit of utilising the broader spectrum of light while also being recoverable.The in-depth analysis of magnesium ferrites'photocatalytic mechanism could lead to the development of cheap and reliable photocatalyst for the wastewater treatment.This concise review offers a thorough summary of the key advancements in this field,highlighting the pivotal role of the magnesium ferrite based photocatalysts in addressing the pressing global issue of organic pollutants in wastewater.

Precipitation and anthropogenic activities regulate the changes of NDVI in Zhegucuo Valley on the southern Tibetan Plateau

Whether climate change or anthropogenic activities play a more pivotal role in regulating vegetation growth on the Tibetan Plateau is still controversial.A better understanding on grassland changes at a fine scale may provide important guidance for local government policy and grassland management.Using two of the most reliable satellite NDVI products(MODIS NDVI and SPOT NDVI),we evaluated the dynamic of grasslands in the Zhegucuo valley on the southern Tibetan Plateau from 2000 to 2020,and analyzed its driving factors and relative influences of climate change and anthropogenic activities.Here,the key indicators of climate change were assumed to be precipitation and temperature.The main results were:(1)the grassland NDVI in Zhegucuo valley did not reflect a significant temporal change during the last 21 years.The variation of precipitation during the early growing season(GSP)resembled that of NDVI,and the GSP was positively correlated with NDVI.At the pixel level,the partial correlation analysis showed that 37.79%of the pixels depicted a positive relationship between GSP and NDVI,while 11.32%of the pixels showed a negative relationship between temperature during the early growing season(GST)and NDVI.(2)In view of the spatial distribution,the areas mainly controlled by GSP were generally distributed in the southern part,while those affected by GST stood in the eastern part,mainly around the Zhegucuo lake where most population in Cuomei County settled down.(3)Decreasing NDVI trends were mainly occurred in alpine steppe at lower elevations rather than alpine meadow at higher elevations.(4)The residual trend(RESTREND)analysis further indicated that the anthropogenic activities played a more pivotal role in regulating the annual changes of NDVI rather than climate factors in this area.Future studies should pay more attention on climate extremes rather than the simple temporal trends.Also,the influence of human activities on alpine grassland needs to be accessed and fully considered in future sustainable management.

Peri-implant gas accumulation in response to magnesium-based musculoskeletal biomaterials:Reframing current evidence for preclinical research and clinical evaluation

Historically,the rapid degradation and massive gas release from magnesium(Mg)implants resulted in severe emphysema and mechanical failure.With the advent of new alloys and surface treatment methods,optimized Mg implants have re-entered clinics since last decade with reliable performance.However,the optimization aims at slowing down the degradation process,rather than exemption of the gas release.This study involved a systematic evaluation of current preclinical and clinical evidence,regarding the physical signs,symptoms,radiological features,pathological findings and complications potentially associated with peri±implant gas accumulation(PIGA)after musculoskeletal Mg implantation.The literature search identified 196 potentially relevant publications,and 51 papers were enrolled for further analysis,including 22 preclinical tests and 29 clinical studies published from 2005 to 2023.Various Mg-based materials have been evaluated in animal research,and the application of pure Mg and Mg alloys have been reported in clinical follow-ups involving multiple anatomical sites and musculoskeletal disorders.Soft tissue and intraosseous PIGA are common in both animal tests and clinical follow-ups,and potentially associated with certain adverse events.Radiological examinations especially micro-CT and clinical CT scans provide valuable information for quantitative and longitudinal analysis.While according to simulation tests involving Mg implantation and chemical processing,tissue fixation could lead to an increase in the volume of gas cavity,thus the results obtained from ex vivo imaging or histopathological evaluations should be interpreted with caution.There still lacks standardized procedures or consensus for both preclinical and clinical evaluation of PIGA.However,by providing focused insights into the topic,this evidence-based study will facilitate future animal tests and clinical evaluations,and support developing biocompatible Mg implants for the treatment of musculoskeletal disorders.

Melatonin delays leaf senescence in pak choi(Brassica rapa subsp.chinensis)by regulating biosynthesis of the second messenger cGMP

Melatonin(MT)is a low molecular weight compound with multiple biological functions in plants.It is known to delay leaf senescence in various species.However,no data are available on the MT signaling pathway in postharvest vegetables.This study demonstrates that MT increases cGMP concentration and the expression of the cGMP synthesis gene BcGC1 in pak choi.The c GMP inhibitor LY83583 destroys effect of MT delaying the leaf senescence.LY83583 also prevents MT treatment from reducing the expression of chlorophyll metabolism-related genes(BcNYC1,BcNOL,BcPPH1/2,BcSGR1/2,and BcPAO)and senescence genes(BcSAG12 and BcSAG21).It also inhibits MT from reducing the activity of the key chlorophyll catabolism enzymes Mg-dechelatase,pheophytinase,and pheide a oxygenase.Thus,the ability of MT to maintain high levels of chlorophyll metabolites is also destroyed.The Arabidopsis c GMP synthetic gene mutant atgc1 was used to confirm that delayed leaf senescence caused by MT is mediated,at least in part,by the second messenger c GMP.

An efficient and mild recycling of waste melamine formaldehyde foams by alkaline hydrolysis

Melamine formaldehyde foam(MFF)generates many poisonous chemicals through the traditional recycling methods for organic resin wastes.Herein,a high MFF degradation ratio of ca.97 wt.%was achieved under the mild conditions(160℃)in a NaOH–H2O system with ammelide and ammeline as the main degradation products.The alkaline solvent had an obvious corrosion effect for MFF,as indicated by scanning electron microscopy(SEM).The reaction process and products distribution were studied by Fourier-transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS),and ^(13)C nuclear magnetic resonance(NMR).Besides,the MFF degradation products that have the similar chemical structures and bonding performances to those of melamine can be directly used as the raw material for synthesis of melamine urea-formaldehyde resins(MUFs).Moreover,the degradation system demonstrated here showed the high degradation efficiency after reusing for 7 times.The degradation process generated few harmful pollutants and no pre-or post-treatments were required,which proves its feasibility in the safe removal or recovery of waste MFF.

Progress and prospects of Mg-based amorphous alloys in azo dye wastewater treatment

Mg-based amorphous alloys exhibit efficient catalytic performance and excellent biocompatibility with a promising application probability,specifically in the field of azo dye wastewater degradation.However,the problems like difficulty in preparation and poor cycling stability need to be solved.At present,Mg-based amorphous alloys applied in wastewater degradation are available in powder and ribbon.The amorphous alloy powder fabricated by ball milling has a high specific surface area,and its reactivity is thousands of times better than that of gas atomized alloy powder.But the development is limited due to the high energy consumption,difficult and costly process of powder recycling.The single roller melt-spinning method is a new manufacturing process of amorphous alloy ribbon.Compared to amorphous powder,the specific surface area of amorphous ribbon is relatively lower,therefore,it is necessary to carry out surface modification to enhance it.Dealloying is a way that can form a pore structure on the surface of the amorphous alloys,increasing the specific surface area and providing more reactive sites,which all contribute to the catalytic performance.Exploring the optimal conditions for Mg-based amorphous alloys in wastewater degradation by adjusting amorphous alloy composition,choosing suitable method to preparation and surface modification,reducing cost,expanding the pH range will advance the steps to put Mg-based amorphous alloys in industrial environments into practice.

Understanding the oxidation chemistry of Ti_(3)C_(2)T_(x)(MXene)sheets and their catalytic performances

Transition metal carbides and nitrides(MXenes)nanosheets are attractive two-dimensional(2D)materials,but they suffer from oxidation/degradation issues during storage and/or applications due to their sensitivity to water and oxygen.Despite the great research progress,the exact oxidation kinetics of Ti_(3)C_(2)T_(x)(MXene)and their final products after oxidation are not fully understood.Herein,we systematically tracked the oxidation process of few-layer Ti_(3)C_(2)T_(x) nanosheets in an aqueous solution at room temperature over several weeks.We also studied the oxidation effects on the electrocatalytic properties of Ti_(3)C_(2)T_(x) for hydrogen evolution reaction and found that the overpotential to achieve a current density of 10 mA cm^(-2)increases from 0.435 to 0.877 V after three weeks of degradation,followed by improvement to stabilized values of around 0.40 V after eight weeks.These results suggest that severely oxidized MXene could be a promising candidate for designing efficient catalysts.According to our detailed experimental characterization and theoretical calculations,unlike previous studies,black titanium oxide is formed as the final product in addition to white Ti(IV)oxide and disordered carbons after the complete oxidation of Ti_(3)C_(2)T_(x).This work presents significant advancements in better understanding of 2D Ti_(3)C_(2)T_(x)(MXene)oxidation and enhances the prospects of this material for various applications.